In a recent year, the scores for the reading portion of a
test were normally distributed, with a mean of 23.8 and a
standard deviation of 5.2.
Complete parts (a) through (d) below.
(a) Find the probability that a randomly selected high school
student who took the reading portion of the test has a score that
is less than 21. The probability of a student scoring less
than 21 is 0.2953 (Round to four decimal places
as needed.)
(b) Find the probability that a randomly selected high
school student who took the reading portion of the test has a score
that is between 17.2 and 30.4. The probability
of a student scoring between 17.2 and 30.4 is 0.7956 (Round to
four decimal places as needed.)
(c) Find the probability that a randomly selected high school
student who took the reading portion of the test has a score that
is more than 34.6.
The probability of a student scoring more than 34.6 is 0.0189
(Round to four decimal places as needed.)
(d) Identify any unusual events. Explain your reasoning. Choose
the correct answer below.
A.The events in parts(a) and (b) are unusual because
its probabilities are less than 0.05.
B.The event in part (c) is unusual because its probability is less
than 0.05.
C. The event in part (a) is unusual because its probability is
less than 0.05.
D.
None of the events are unusual because all the probabilities are greater
than 0.05.